Handling dc subcarrier in narrow bandwidth communications

ABSTRACT

According to some embodiments, a user equipment (UE) and a method in the UE are disclosed. The UE is served by a cell managed or served by a network node. The UE comprises processing circuitry, a transceiver coupled to the processing circuitry, and memory containing instructions executable by the processing circuitry. The UE is operative to determine that a center frequency of a radio frequency (RF) reception bandwidth of the UE is different than a center frequency of a RF transmission bandwidth of the cell serving the UE. The UE is further operative to receive a signal from the cell serving the UE over a center subcarrier within the RF reception bandwidth of the UE, and puncture a portion of the signal received over the center subcarrier within the RF reception bandwidth of the UE.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 15/562,476, filed on Sep. 28, 2017, which is a National Stage Entryof PCT International Application No. PCT/EP2016/058318, filed on Apr.15, 2016, which claims the benefit of and priority to U.S. ProvisionalPatent Application No. 62/150,030, filed on Apr. 20, 2015, thedisclosure and content of each of which are incorporated herein byreference in their entireties.

TECHNICAL FIELD

The present application relates to wireless communications systems, andmore particularly, to allocation of radio resources to wirelesscommunications devices.

BACKGROUND

Machine Type Communication (MTC), also referred to as Machine to Machine(M2M) communications, refers to wireless and wired communicationsbetween devices. MTC has a wide range of applications, includingindustrial automation, logistics, monitoring but also for controlpurposes.

MTC is widely used for industrial instrumentation applications in whicha device, such as a sensor or meter, captures real-time data, such astemperature, inventory level, error reports, surveillance images, etc.,and transmits the captured data to a data collection node. In additionto instrumentation, MTC is also being widely adopted for otherapplications, such as telemetry and automation.

MTC may incorporate the transmission of many types of information,including user data, signaling information, measurement data,configuration information, etc. The device size may vary from that of awallet to that of a base station. M2M devices are quite often used forapplications, such as sensing environmental conditions (e.g. temperaturereading), metering or measurement (e.g. electricity usage etc.), faultfinding or error detection, etc. In these applications the MTC devicesare active very seldom but over a consecutive duration depending uponthe type of service e.g. about 200 ms once every 2 seconds, about 500 msevery 60 minutes etc. The MTC device may also do measurement on otherfrequencies or other Radio Access Technologies (RATs).

One category of MTC devices is referred to as “low cost devices.” Forexample, a cost reduction can be realized by relaxing the requirementson peak rate and receiver performance LTE Release 12 introduces a lowcost user equipment (UE) category called UE category 0 with a relativelylow peak rate of 1 Mbps and relaxed performance requirements that can befulfilled having just a single antenna receiver in the UE. The cost canbe further reduced by supporting only half duplex frequency divisionduplexing (FDD) capability instead of full duplex FDD capability. Thelatter feature prevents the need for having duplex filter since UE doesnot transmit and receive at the same time.

The RF bandwidth (BW) of the legacy LTE UE is 20 MHz. In legacy LTEsystems, the UE reception BW and cell transmission BW have the samecenter frequencies. Similarly, in legacy LTE system, the UE transmissionBW and cell reception BW have the same center frequencies. However, costreduction may be achieved by having a reduced UE RF bandwidth. Forexample, for LTE Release 13, cost reduction may be realized by having areduced UE RF bandwidth of 1.4 MHz comprising six (6) resource blocks(RBs).

For MTC UEs with reduced RF bandwidth (1.4 MHz) the UE can be scheduledwith up to 6 physical resource blocks (PRBs) in any part of the cell BWif the cell BW is larger than 1.4 MHz. A minimum allocation of 1 PRB forboth the uplink (UL) and downlink (DL) can be supported. For example, ifthere are 5 MTC UEs in the same cell of 20 MHz BW. Then one can beconfigured in the center of the cell BW, with 2 UEs on the lower part ofthe cell BW and the remaining 2 UEs on the upper part of the cell BW.

Furthermore, the frequency of the MTC UE can also be re-tuned to supportfrequency multiplexing of users and to support frequency hopping acrossthe cell BW. For example, a UE configured at a lower portion of the cellBW in a certain frame or subframe can be re-tuned to another part of thecell BW in another frame or subframe.

Narrow bandwidth MTC operation may also be referred to as narrow bandoperation or narrow band MTC operation. Currently in LTE the following 6RF bandwidths are supported: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and20 MHz.

In flexible BW operation, UEs with a narrow bandwidth (i.e. an RF BWsmaller than the cell BW) can be operated by the network nodeconfiguring them in any part of the cell BW. Furthermore, the UE andcell BW may be any possible BW with a resolution of one resource block(RB). As an example, in a cell of 20 MHz, two UEs with an RF BW of 6 MHzeach may be configured to operate on a lower and an upper part of thecell BW, respectively. They may also be configured to operate withpartial or full overlapping of their BWs within the cell. Flexible BWoperation is similar to narrow BW MTC operation, except that in the caseof flexible BW operation, there can be a larger number of possible RFBWs of the UE and of the cell.

SUMMARY

A method in a network node serving a user equipment includes configuring(202) the UE in a cell to operate with a center frequency of a radiofrequency, RF, reception bandwidth of the UE being different than acenter frequency of an RF transmission bandwidth of the cell; puncturing(204) a subcarrier in a downlink signal that, when transmitted over theRF transmission bandwidth corresponds to the center frequency of the UERF reception bandwidth to provide a punctured downlink signal; andtransmitting (206) the punctured downlink signal to the UE through atransmitter circuit operating within the UE RF reception bandwidth.

The method may further include modifying an RF reception bandwidth of asecond UE in the cell such that a center frequency of the modified RFreception bandwidth of the second UE corresponds to the puncturedsubcarrier.

The method may further include moving (302) transmission of a controlsignal from a subcarrier that corresponds to the center frequency of thereception bandwidth of the UE to a subcarrier that does not correspondto the center frequency of the reception bandwidth of the UE.

The method may further include informing (314) the UE that the controlsignal has been moved to the subcarrier that does not correspond to thecenter frequency of the reception bandwidth of the UE.

The method may further include selecting a control signal that is to bemoved from a subcarrier that corresponds to the center frequency of thereception bandwidth of the UE to a subcarrier that does not correspondto the center frequency of the reception bandwidth of the UE based on arecommendation provided by the UE.

The method may further include selecting a control signal that is to bemoved from a subcarrier that corresponds to the center frequency of thereception bandwidth of the UE to a subcarrier that does not correspondto the center frequency of the reception bandwidth of the UE based on afrequency of use of the control signal for performing a measurement atthe UE, a frequency of transmission of the control signal, and/or asignificance of the control signal.

The method may further include informing the UE that the subcarrier thatcorresponds to the center frequency of the UE RF reception bandwidth hasbeen punctured.

The method may further include moving (322) transmission of a datasignal from a subcarrier that corresponds to the center frequency of thereception bandwidth of the UE to a subcarrier that does not correspondto the center frequency of the reception bandwidth of the UE.

The method may further include informing (324) the UE that the datasignal has been moved to the subcarrier that does not correspond to thecenter frequency of the reception bandwidth of the UE.

The method may further include selecting a channel stateinformation-reference signal (CRI-RS) configuration that does notutilize the punctured subcarrier, and transmitting the CRI-RS signal tothe UE.

A method in a network node serving a user equipment, UE, includesconfiguring (402) the UE in a cell to operate with a center frequency ofa radio frequency, RF, reception bandwidth of the UE being differentthan a center frequency of an RF transmission bandwidth of the cell;moving (404) a control signal being transmitted by a transmitter circuitusing a subcarrier that corresponds to the center frequency of the RFreception bandwidth of the UE to being transmitted using a subcarrierthat does not correspond to the center frequency of the RF receptionbandwidth of the UE; instructing (406) the UE to puncture the subcarrierin a downlink signal that corresponds to the center frequency of the UERF reception bandwidth; and transmitting (408) the downlink signal tothe UE through a transmitter circuit.

The UE may includes a first UE, and the method may further includemodifying (412) an RF reception bandwidth of a second UE in the cellsuch that a center frequency of the modified RF reception bandwidth ofthe second UE corresponds to the center frequency of the first UE; and

instructing (414) the second UE to puncture (204) the subcarrier in thedownlink signal that corresponds to the center frequency of the RFreception bandwidth of the second UE.

The method may further include informing the UE that the control signalhas been moved to the subcarrier that does not correspond to the centerfrequency of the RF reception bandwidth of the UE.

A method in a user equipment, UE, served by a cell managed or served bya network node, includes determining (212) that a center frequency of aRF reception bandwidth of the UE is different than a center frequency ofthe RF transmission bandwidth of the cell serving the UE; receiving(214) a signal from the cell serving the UE over the RF receptionbandwidth; and puncturing (216) the portion of the signal receivedthrough a receiver circuit operating in the center subcarrier within theUE RF reception bandwidth.

The method may further include modifying one or more procedures toreduce a performance degradation of one or more radio operations thatutilize or rely on one or more radio signals received over the centerfrequency at the UE RF receiver bandwidth.

Puncturing the portion of the signal received over the center subcarrierwithin the UE RF reception bandwidth may include performing a fastFourier transform of the signal to generate a plurality of frequencybins and zeroing a frequency bin corresponding to the center subcarrier.

A network node serving a UE according to some embodiments includes aprocessor (820); a transceiver (810) coupled to the processor; and amemory (830) coupled to the processor, the memory including computerreadable program code embodied therein that, when executed by theprocessor, causes the processor to perform operations includingconfiguring (202) the UE in a cell such that a center frequency of an RFreception bandwidth of the UE is different than a center frequency of anRF transmission bandwidth of the cell; puncturing (204) a subcarrier ina downlink signal that, when transmitted over the RF transmissionbandwidth corresponds to the center frequency of the UE RF receptionbandwidth to provide a punctured downlink signal; and transmitting (206)the punctured downlink signal to the UE within the UE RF receptionbandwidth.

The computer readable program code may further cause the processor toperform operations that include adapting transmission of one or morecontrol/data radio signals within the UE RF reception bandwidth of theUE to avoid transmission of the control/data radio signals over thesubcarrier that corresponds to the center frequency within the UE RFreception bandwidth.

A user equipment, UE, served by a cell managed or served by a networknode, includes a processor (700); a transceiver (710) coupled to theprocessor; and a memory (720) coupled to the processor, the memoryincluding computer readable program code embodied therein that, whenexecuted by the processor, causes the processor to perform operationsthat include determining (212) that a center frequency of a RF receptionbandwidth of the UE is different than a center frequency of the RFtransmission bandwidth of the cell serving the UE; receiving (214) asignal from the cell serving the UE over the RF reception bandwidth; andpuncturing (216) the signal received over the center subcarrier withinthe UE RF reception bandwidth.

The computer readable program code may further cause the processor toperform operations that include modifying one or more procedures toreduce a performance degradation of one or more radio operations thatutilize or rely on one or more radio signals received over the centerfrequency at the UE RF receiver bandwidth.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are schematic diagrams that illustrate a transmissionbandwidth of a network node and a reception bandwidth of a UE.

FIGS. 3 and 4 are flowcharts illustrating operations according to someembodiments.

FIG. 5 is a block diagram illustrating a network node and transceiversthat are configured according to some embodiments.

FIGS. 6, 7 and 8 are schematic diagrams that illustrate a transmissionbandwidth of a network node and a reception bandwidth of one or moreUEs.

FIGS. 9A, 9B and 9C are flowcharts illustrating operations according tosome embodiments.

FIGS. 10A and 10B are flowcharts illustrating operations according tosome embodiments.

FIG. 11 is a block diagram of a device that is configured to performoperations according to one or more embodiments.

FIG. 12A is a block diagram of a network node that is configuredaccording to one or more embodiments.

FIG. 12B is a block diagram that illustrates the functional modules in amemory of a network node that is configured according to one or moreembodiments.

DETAILED DESCRIPTION

Embodiments of the present inventive concepts now will be described morefully hereinafter with reference to the accompanying drawings. Theinventive concepts may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the inventiveconcepts to those skilled in the art. Like numbers refer to likeelements throughout.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present inventiveconcepts. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a”, “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises,” “comprising,”“includes” and/or “including” when used herein, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms used herein should be interpreted ashaving a meaning that is consistent with their meaning in the context ofthis specification and the relevant art and will not be interpreted inan idealized or overly formal sense unless expressly so defined herein.

Some embodiments described herein provide systems and/or methods forhandling the DC subcarrier, or center frequency, of a signal received bya narrow bandwidth (BW) device, i.e., where the BW of the device is lessthan the BW of the cell, and the received signal and the cell do notshare the same center frequency.

The DC subcarrier is the subcarrier whose frequency is equal to the RFcenter frequency of the transmitting radio node. In the baseband signalthis subcarrier corresponds to frequency zero, which means a directcurrent (DC) component in the baseband signal. In order to limit themagnitude of the signal which causes inefficiency in the digital toanalog (D/A) and analog to digital (A/D) converters, the DC subcarrieris usually nulled.

Also in some user equipment (UE) implementations (e.g. homodyne ordirect conversion receivers), when the received radio signal isdown-converted to baseband, the mixing of the center frequency of thereceived signal and the local oscillator (LO) frequency can result in astrong direct current (DC) component being generated. This is oftenreferred to as a DC offset or an LO leakage. It is referred to “DC”since it appears at frequency zero in a baseband representation of thesignal. This DC component can be detrimental to the signal reception inseveral ways. For example, if the DC component is too large, it maycause the analog-to-digital conversion (ADC) of the baseband signal tosaturate.

When the transmitter and the receiver have the same center frequency, bynulling the DC subcarrier at the transmitter, the DC subcarrier at thereceiver will be zero as well, and the problem on both sides is solved.However, if the center frequency at the transmitter and the receiver arenot the same, nulling the DC subcarrier at the transmitter does notsolve the problem at the receiver.

FIG. 1 illustrates an example in which the center frequencies of the TXand RF bandwidths are aligned. Note that the DC subcarrier at the centerfrequency is nulled by the transmitter.

In this case, the DC subcarrier is the same for both TX and RX in asingle direction (e.g., the uplink (UL) or downlink (DL)). That is, inthe example illustrated in FIG. 1, although the transmitter TX has alarger bandwidth than the receiver RX, the transmitter bandwidth and thereceiver bandwidth are both centered on the same center frequency. Ingeneral, however, this need not be the case. Using DL communications asan example, a transmitting base station may transmit over a bandwidththat is larger than the bandwidth of a receiving UE, which may, forexample, be a narrow bandwidth M2M device. The receiving UE may beallocated subcarriers in such a manner that the center frequency of thereceiver is offset from the center frequency of the transmitter.

It shall be noted that the terms “DC subcarrier” and “center frequency”are used interchangeably herein. They may refer to a systemcharacteristic, namely corresponding to the center frequency of acarrier in a telecommunications system. In an LTE system, this maycorrespond to the center frequencies of the DL and UL carriers used by abase station, i.e., eNodeB (eNB). In an FDD system, the DL and ULcarrier center frequencies are different, whereas in a TDD system theyare equal. “DC subcarrier” and “center frequency” may also refer to animplementation specific frequency, most notably the location of thelocal oscillator frequency in a direct conversion receiver ortransmitter.

In the following description, it is assumed that the receiver employs adirect-conversion architecture, i.e. that its center frequency and DCsubcarrier coincide. For simplicity, it is also assumed that the TXrefers to an LTE eNB, and the receiver refers to an LTE UE (i.e. an LTEdownlink scenario), but the description applies also to other systems,scenarios and configurations.

If the center frequency of the base station (BS) transmitter and the UEreceiver or the UE transmitter and the BS receiver are not the same,even though the transmitter may put zero on the DC subcarrier, thereceiver will have non-zero DC subcarrier.

FIG. 2 illustrates an example where the center frequencies of the RFbandwidths on the TX and RX sides are not aligned. As a result, thecenter frequency on the RX side (corresponding to the DC subcarrier)contains a non-zero symbol.

As an example of such a scenario is the case of narrowband UEs for MTCthat are planned to be introduced as part of LTE Release 13 [RP-141660].In this case the UE bandwidth can be for example 6 physical resourceblocks (PRBs) anywhere within a larger system bandwidth, and furthermorethe center frequency of the UE can be different than that of the eNB,resulting in the DC subcarrier at the UE receiver being nonzero.

According to some embodiments, when the center frequencies (e.g., DC orcenter subcarriers) of a cell's RF transmission bandwidth and of the RFreception bandwidth of a UE configured in the cell are not the same,then a network node or the UE may puncture the center frequency at theUE RF reception BW. The network node may also adapt a transmissionlocation of one or more predetermined signals (e.g., DMRS, etc.) in atleast the frequency domain within the cell transmission BW to avoid thepuncturing of the predetermined signals. The UE may also adopt one ormore procedures to reduce the performance loss of one or more operationswhich use the radio signals received over the center subcarrier. Thenetwork node may also inform the UE as to whether or not the UE isallowed to puncture the center subcarrier.

Referring to FIG. 3, some particular embodiments provide a method in anetwork node serving a UE. The method as implemented in a network nodeincludes configuring a UE in a cell such that the center frequency ofthe UE receiver is different than the center frequency of an RFtransmission BW of the cell (block 202), puncturing the subcarrier whichcorresponds to the center frequency at the UE RF reception BW (block204), and transmitting the adapted radio signals within the UE RFreception BW (block 206).

In some embodiments, the method may include adapting one or more radiosignals within the UE RF reception BW based on one or more criteriatransmission. The adaptation may avoid the transmission of predeterminedradio signals over the subcarrier which corresponds to the centerfrequency within the UE RF reception BW.

Some embodiments provide a method in a UE served by a cell managed orserved by a network node. Referring to FIG. 4, the method as implementedin a UE includes determining that a center frequency of the UE's RFreception BW is different than the center frequency of the RFtransmission BW of the cell serving the UE (block 212), receiving asignal from the cell serving the UE over the UE's RF reception bandwidth(block 214), and puncturing or nulling the signal received over thecenter subcarrier within the UE RF reception BW (block 216).

These embodiments may further include adapting one or more procedures atthe UE to reduce or minimize performance degradation of one or moreradio operations that utilize or rely on one or more radio signalsreceived over the center frequency at the UE RF receiver BW.

By transmitting/receiving signals in this manner, some embodiments mayenable the use of UEs having an RF bandwidth that is smaller than the RFBW of the system (i.e. serving cell) in manner that can be operatedefficiently.

Some embodiments may provide more freedom in using wireless devices ofdifferent RF bandwidths within the same cell with more freedom in termsof scheduling. For example, UEs can be configured in different parts ofthe cell bandwidth. This can be realized without adding more complexityon the hardware side due to dynamic range in the analog to digital (A/D)conversion of the UE.

Furthermore, some embodiments can be implemented in such a way that theperformance of radio operations that use signals received over thecenter frequency (e.g. DC subcarrier) of the UE RF reception BW are notdegraded, or the degradation, if any, is reduced or minimized.

FIG. 5 is a schematic diagram illustrating a communication system inwhich two UEs 100A, 100B communicate with a network node 800A. In thisdescription, a more general term “network node” may be used instead of“base station” or “eNodeB.” A network node can correspond to any type ofnode in a radio network that communicates with a UE and/or with anothernetwork node. Examples of network nodes are NodeB, MeNB, SeNB, a networknode belonging to MCG or SCG, base station (BS), multi-standard radio(MSR) radio node such as MSR BS, eNodeB, network controller, radionetwork controller (RNC), base station controller (BSC), relay, donornode controlling relay, base transceiver station (BTS), access point(AP), transmission points, transmission nodes, RRU, RRH, nodes indistributed antenna system (DAS), core network node (e.g. MSC, MME etc),O&M, OSS, SON, positioning node (e.g. E-SMLC), MDT etc.

In some embodiments the non-limiting term user equipment (UE) is usedand it refers to any type of wireless device communicating with anetwork node and/or with another UE in a cellular or mobilecommunication system. Examples of UE are target device, device to device(D2D) UE, machine type UE or UE capable of machine to machine (M2M)communication, PDA, PAD, Tablet, mobile terminals, smart phone, laptopembedded equipped (LEE), laptop mounted equipment (LME), USB donglesetc.

In some embodiments, the term “radio node” may be used to refer to aradio network node or a UE. Thus, in the example illustrated in FIG. 5,both the devices 100A, 100B and the network node 800 are radio nodes.

The terms cell bandwidth (BW), system BW, channel bandwidth, RF systembandwidth, cell transmission BW, cell reception BW, cell operational BW,full BW, full cell or system BW are used interchangeably and have thesame meaning. Each of these terms refers to the BW of cell whenoperating over the full BW of the cell, e.g. using the maximum number ofavailable physical channels, such as RBs. For example, an RF BW of 10MHz may contain 50 RBs. The RF BW of a channel is typically expressed inunits of frequency e.g. Hz, MHz, etc. The channel BW is expressed interms of a number of channels, e.g. RBs, PRBs, VRBs, etc. For example,an RF BW of 1.4 MHz may correspond to a channel BW of 6 RBs.

Accordingly, a narrow BW device may have fewer channels (e.g. 6 RBs)than that available within the full BW (e.g. 50 RBs). A flexible BWsystem may have fewer channels (e.g. 30 RBs) than are available withinthe full system BW (e.g. 100 RBs). The embodiments described hereinapply to any narrow BW operation or narrow RF BW, i.e. narrower RF BW ofa UE compared to the system or cell RF BW. The terms narrow BW, narrowRF BW, narrow BW for MTC, flexible BW, flexible RF BW, restricted BW,restricted RF BW, smaller BW or smaller RF BW etc., may be usedinterchangeably and have the same meaning.

A resource block (RB) is one particular example of a physical channel.Non-limiting examples of physical channels are time-frequency resource,radio channels, resource elements (REs), physical resource blocks(PRBs), resource blocks (RBs), virtual resource blocks (VRBs), etc.

Examples of signals that are intended to be received at the UE includethe physical channel and physical signals. A physical channel carrieshigher layer information, e.g. user data, RRC signaling, etc. A physicalsignal carriers or is encoded with a physical layer signals such asreference signals, physical cell ID etc. Examples of physical channelsare data channel (e.g. PDSCH), control channels (e.g. PDCCH, EPDCCH,PHICH, PCFICH etc), common channel (e.g. PBCH) etc. Examples of physicalsignals are reference signals or pilot signals (e.g. CRS, PRS, discoverysignals, PSS, SSS, CSI-RS, DMRS, MBSFN RS etc).

Examples of signals or channels whose interference from one or moreinterfering cells at the UE can be mitigated by the UE in LTE are PDSCH,PDCCH, PCFICH, PCFICH, EPDCCH, PBCH, CRS, PRS, etc.

Example embodiments set forth herein are described for a single carrier(i.e., single carrier operation of the UE) in a network node. However,the embodiments are also applicable for multi-carrier or carrieraggregation (CA) operation of the UE, i.e., when network node transmitsand/or plurality of serving cells on different carriers (aka CCs) to thesame UEs. The serving cell on PCC is referred to as the primary cell(PCell), whereas the serving cell on SCC is referred to as the secondarycell (SCell). Dual connectivity (DC) is a special case of CA where theCCs assigned to the UE operate from different base station sites, e.g.different eNode Bs (aka, master eNB (MeNB) and secondary eNB (SeNB)). Atleast one serving cell in MeNB, called the PCell, and one serving cellin SeNB, called the PSCell, contain both UL and DL. The embodimentsshall apply to each carrier in UL and/or DL in DC or CA.

1. Method in a Network Node to Null Subcarriers Corresponding to theCenter Subcarriers of the UE Receiver RF Bandwidth

In a first method according to embodiments of the inventive concepts,the network node may not send any signal in the subcarrier that willcorrespond to the center frequency of the receiver RF bandwidth of theUE. This is referred to herein as zeroing a subcarrier or nulling asubcarrier. This approach is based on the knowledge, at the networknode, of the receiver RF bandwidth of the UE. To determine thesubcarrier to be nulled, the transmitting network node determineswhether or not the center subcarrier of the UE RF receiver is differentthan the center subcarrier of the cell RF transmitter. If their centerfrequencies are not the same then the network node nulls the subcarrierwithin its transmit bandwidth that is received as the center subcarrierby the UE RF receiver. The network node may apply the same method forall the UEs whose RF receivers are not tuned in the center frequency ofthe RF transmitter of the network node.

FIG. 6 shows an example of a case where a network node deliberately putsa zero at the subcarrier that corresponds to the DC subcarrier at the UEreceiver side.

This embodiment guarantees a zero subcarrier at the receiver side. Inaddition, although not illustrated in FIG. 6, the DC subcarrier at thetransmitter side may also be nulled as is done, for example, in thecurrent LTE downlink signal.

The method can be done on as many subcarriers corresponding to thenumber of UEs as are scheduled in a given subframe within the cellbandwidth. This means that several subcarriers may carry zero in allsymbols containing such subcarriers to avoid DC subcarrier problem inmultiple UEs. This will allow the UE to receive signals from the basestation using existing techniques, i.e. using the same receiver as whenthe UE receiver is tuned at center of cell BW. However, there may beperformance degradation at the UE if the center subcarrier which isnulled contains important data or control signals.

A pre-defined rule may be specified stating that the network node willpuncture the subcarrier corresponding to the center frequency of the UERF receiver BW. Alternatively, the UE may be informed whether thenetwork node or UE has to puncture the center subcarrier.

2. Method in a Network Node of Adapting Configuration to AvoidControl/Data Signals Coinciding with Center Subcarrier at UE RF Receiver

In this embodiment it is assumed that either the network node or the UEmay null the center frequency at the UE RF receiver. If the centerfrequency of the UE RF receiver contains signals specifically providedto support one or more operations, then the performance of suchoperations may be degraded by puncturing at the transmitter. Examples ofsignals that are transmitted by the network node and used by the UEreceiver for particular operations are control signals, common channelsignals (e.g. PBCH etc) and reference signals (e.g. CRS, PRS, PSS, SSS,DMRS etc).

For example, if several subcarriers carrying Cell-specific ReferenceSignals (CRS) used for mobility measurements such as RSRP and RSRQ(which are power and quality measurements, respectively) are punctured,then the measurement results may incorporate large errors. Therefore, amobility decision may be erroneous, e.g. a handover may be performed toa cell that is not necessarily the strongest cell in terms of signalstrength and/or signal quality. In yet another example, if severalsubcarriers carrying PRS used for positioning measurements are puncturedor nulled, then the measurement results may incorporate large error.This in turn will cause a larger error in the positioning of the UE.

However, puncturing one subcarrier at the UE may result in a certainloss in performance. If the punctured subcarrier carries a data symbol(e.g. PDSCH), removing one such symbol usually results in minorperformance loss e.g. SNR degradation by 0.5 dB or less.

To avoid performance degradation due to nulling of control/data signals,the network node may adapt the configuration of the network node and/orthe UE. The following three mechanisms may apply such adaptations:

a. Adaptation of signals coinciding with the center subcarrier at the UERF receiver. Data/control signals that would otherwise fall at thecenter subcarrier of the UE RF receiver may be moved to othersubcarriers.

b. Adaptation of UE RF receiver bandwidth within the cell BW to avoidoverlapping between control/data signals and the center subcarrier at UERF receiver. The bandwidth of the UE RF receiver may be modified to movethe center subcarrier at the UE RF receiver away from subcarrierscarrying particular control/data signals. This approach is illustrated,for example, in FIG. 7. As shown therein, a center frequency of areceiver bandwidth may correspond to a subcarrier on which a particularcontrol/data signal is carried. The network node may adapt the UEreceiver bandwidth or assigned RBs so that the center frequency of theUE receiver bandwidth is no longer aligned with the subcarrier thatcarries the control/data signal. The receiver may then null its centerfrequency without loss of the desired control/data signal.

FIG. 8 illustrates an embodiment in which the network node nulls atransmission carrier. The punctured (or nulled) subcarrier maycorrespond to the center frequency of the bandwidth RX1 of a first UE,but not with the bandwidth RX2 of a second UE. The network node maymodify the receiver bandwidth or assigned RBs of the second UE such thatthe center frequency of the modified bandwidth is aligned with thepunctured subcarrier. This approach is further illustrated in the blockdiagram of FIG. 9A, which illustrates that a network node may modify thereception bandwidth of a second UE such that a center frequency of themodified RF reception bandwidth of the second UE corresponds to thepunctured subcarrier (block 302).

c. A Combination of Adaption of Control/Data Signals and UE RF ReceiverBW.

2.1 Method in a Network Node of Adapting Transmission of Control/DataSignals Coinciding with Center Subcarrier at UE RF Receiver

As noted above, in order to reduce or minimize performance degradationdue to nulling of control/data signals, the network node may adapt theconfiguration of one or more signals such that they are not mapped tothe center subcarrier at the RF receiver of the UE. Some of suchimportant signals can be reference signals such as cell-specificreference signals (CRS), channel state information reference signal(CSI-RS), demodulation reference signal (DMRS), positioning referencesignal (PRS), or other important information such as controlinformation, etc. For example, the network node may deliberatelyconfigure one or more control/data signals (e.g. DMRS) at a location inthe cell BW such that they do not appear at the center frequency of theUE RF receiver BW.

In another example, for a UE with certain known RF receiver bandwidth,the network node selects and configures only those CSI-RS configurationsin the cell that do not coincide with the center subcarrier of the UE RFreceiver BW.

This approach is illustrated in the block diagram of FIG. 9B. As showntherein, a network node may move transmission of a control signal from asubcarrier that corresponds to the center frequency of the receptionbandwidth of a UE to a subcarrier that does not correspond to the centerfrequency of the reception bandwidth of the UE (block 312). The networknode may inform the UE that the control signal has been moved to the newsubcarrier (block 314). Similarly, FIG. 9B illustrates that the networknode may move transmission of a data signal from a subcarrier thatcorresponds to the center frequency of the reception bandwidth of a UEto a subcarrier that does not correspond to the center frequency of thereception bandwidth of the UE (block 322). The network node may informthe UE that the data signal has been moved to the new subcarrier (block324).

The network node may also decide one or more particular type ofcontrol/data signals, which should be prevented from coinciding with thecenter subcarrier of the UE RF receiver, based on one or more criteria.Examples of criteria include:

a. Frequency of using the control/data signals for an operation, e.g.CRS are regularly used for RSRP and RSRS measurements. Therefore, UEshould be tuned to avoid CRS collision with center RF receiversubcarrier.

b. Density of control/data signals in time and/or frequency, e.g. CSI-RSmay be transmitted sparsely. Signals which are not so dense may bemapped away from the center subcarrier of the UE RF receiver.

c. Significance of operation, e.g. PRS used for positioning forcontrol/data services. Signals which are used by the UE for morecontrol/data purposes such as PRS may be mapped away from the centersubcarrier of the UE RF receiver. PRS are used by the UE for performingRSTD measurement which in turn is used for determining UE location underemergency services.

d. Recommendation or indication received from the UE. For example, theUE may identify one or more control/data signals that the UE does notwant to be received over the center subcarrier. The UE may recommendthis to the network node by sending an explicit indication to thenetwork node. For example, the UE may recommend those control/datasignals which are more frequently used or used for control/dataoperation, e.g. DMRS for channel estimation, PRS for positioning etc.,not be mapped to the center frequency.

2.2 Method in a Network Node of Tuning UE RF Receiver BW to AvoidControl/Data Signals Coinciding with Center Subcarrier at UE RF Receiver

In this mechanism in order to reduce or minimize performance degradationdue to nulling of control/data signals, the network node adapts thelocation of the UE RF receiver BW within the cell BW. This is realizedby configuring the UE receiver in the cell such that the centersubcarrier frequency of the UE RF receiver does not coincide with anycontrol/data signal or may coincide with a least or acceptable number ofcontrol/data signals transmitted by the network node.

For example, as illustrated in FIG. 10A, a network node may configure aUE in a cell such that the center frequency of the UE receiver isdifferent than the center frequency of an RF transmission BW of the cell(block 402). The network node may move control signals from a subcarrierthat corresponds to the center frequency of the RF reception bandwidthof the UE to a subcarrier that does not correspond to the centerfrequency of the RF reception bandwidth of the UE (block 404), andinstruct the UE to puncture the subcarrier in a downlink signal thatcorresponds to the center frequency of the UE RF reception bandwidth(block 406). The network node may then transmit the punctured downlinksignal within the UE's RF reception bandwidth (block 408).

In some embodiments, as illustrated in FIG. 10B, the network node maymodify an RF reception bandwidth of a second UE in the cell such that acenter frequency of the modified RF reception bandwidth of the second UEcorresponds to the center frequency of the first UE (block 412) andinstruct the second UE to puncture the subcarrier in the downlink signalthat corresponds to the center frequency of the RF reception bandwidthof the second UE (block 414).

The network node may also identify one or more particular type ofcontrol/data signals that should be mapped away from the centersubcarrier of the UE RF receiver, by the virtue of tuning or retuningthe UE RF receiver BW within the cell BW. Examples of criteria are thesame as described in section 2.1.

2.3 Combination of Tuning UE RF Receiver BW and Adaptation ofTransmission of Control/Data Signals

In this combined mechanism the network node may apply both mechanismsdescribed in sections 2.1 and 2.2. The network node may apply thecombined mechanism in case only one of the methods cannot avoid thecollision of all or certain desired control/data signals with UE thecenter subcarrier of the UE RF receiver BW.

3. Method in a UE to Puncture the Center Subcarrier at the Receiver

In this embodiment the network node may send a non-zero symbol on thecenter subcarrier, which is punctured by the UE when received at the UERF receiver. In this embodiment therefore the network node may performthe normal subcarrier mapping meaning that it does not puncture thesubcarrier corresponding to the DC subcarrier in the receiver, butinstead the UE punctures the DC subcarrier. This can for example be doneusing a high pass analog filter which attenuates the DC component.Another possible method is to let the received signal enter the ADCconverter of the receiver without any DC compensation, subsequentlyperform an FFT operation, and then puncture the frequency bincorresponding to the DC subcarrier.

4. Method in a UE to Adapt Procedure(s) to Minimize Loss Due toPuncturing of the Center Subcarrier of UE RF Receiver

In this embodiment it is assumed that either the network node may send azero symbol (i.e. punctures or nulls) on the subcarrier corresponding tothe center subcarrier at the UE RF receiver or the UE may puncture thecenter subcarrier at the UE RF receiver. This can be realized bysuppressing, discarding or ignoring any signal received over the centersubcarrier.

In this embodiment, the UE adapts one or more procedures to reduce orminimize the degradation in performance of one or more operations usingsignals that are lost, destroyed or otherwise affected due to thenulling of the center subcarrier. Examples of such operations performedby the UE that may be adapted include channel estimation,synchronization, receiver timing adjustment, transmitter timingadjustment based on reception of signals, radio measurements,positioning, etc. For example, operations such as channel estimation mayuse reference signals which may be affected due to falling in the centersubcarrier of the UE RF receiver BW. The loss of such signals may resultin, for example, incorrect estimation of the channel. This in turn maydegrade the data channel reception performance as it relies on thechannel estimation.

Examples of procedures to reduce or minimize or limit the degradation inperformance of one or more operations include:

a. In one example the UE may deliberately not use any signal that isreceived in the center subcarrier of its RF receiver BW for anyoperation. The UE may instead use signals that are received on othersubcarriers. This will require the UE to adapt its receiver depending onwhether the center subcarrier of the UE RF receiver contains certaincontrol/data signals or not. For example, in the former case when takingaverage of the measurement samples obtained on reference signals, the UEmay use only those samples which do not use any signals received in thecenter subcarrier of its RF receiver BW.

b. In a second example the UE may also deliberately not use any signalthat is received in the center subcarrier of its RF receiver BW for anyoperation. However, to compensate the loss, the UE may use similarsignals received in other parts of the RF reception BW for the sameoperation. For example, the UE may obtain more frequent samples ofreference signals in time for measurement on reference signal such asCSI-RS (e.g. one sample every 20 ms instead of every 40 ms) in case oneor more such reference signals received over center subcarrier are lostor discarded at the UE receiver. More frequent measurement sampling willallow the UE to use more samples for averaging and for obtaining thefinal measurement results with negligible or acceptable performancedegradation.

c. In a third example, the UE may not use the signals received in thecenter subcarrier of its RF receiver BW for performing one or moreoperations e.g. radio measurements. However, to reduce or minimize theperformance degradation, the UE may apply some compensation to theresult of the performed operation. The value of compensation may bepre-defined or decided by the UE autonomously. The compensation valuemay also be determined by the UE implicitly based on one or morepre-defined requirements associated with the operation. The compensationvalue may also depend on one or more of the following: the type ofsignals (e.g. CRS, CSI-RS etc) used for an operation, type of operation(e.g. RSRP measurement, channel estimation, positioning measurement),density or frequency of signals in time and/or frequency used foroperation. For example, the UE may apply a fixed compensation of 0.5 dBto the result of radio measurement such as RSRP when the centersubcarrier of UE RF receiver coincides with CRS.

4.1 Realization of Adaption of Procedure(s) by Pre-Defined Requirements

One or more UE requirements or rules may be pre-defined to ensure thatthe UE adapts one or more procedures so as to reduce or minimize theperformance degradation of one or more operations using signals that arelost, destroyed or otherwise affected due to the nulling of the centersubcarrier. Such pre-defined requirements may also ensure that theperformance degradation due to the puncturing of the center subcarriernormally used by the UE for one or more operations is reduced or ismaintained within an acceptable or allowed limit.

Examples of requirements include:

a. SNR or SINR corresponding to certain bit rate or throughput (e.g. 70%of maximum value).

b. Measurement accuracy of a measurement quantity e.g. an accuracy ofRSRP or RSRQ within +/−2 dB of the true measurement value.

c. Timing accuracy of a measurement quantity e.g. an accuracy of RSTDwithin +/−6 Ts of the true measurement value; Ts=32.55 ns.

d. Measurement period or measurement time of measurement quantity e.g.L1 period of RSRP/RSRQ, cell identification time, evaluation time of outof sync or in sync for radio link monitoring etc.

e. Number of cells for which measurements (e.g. RSRP and/or RSRQ) can bemeasured during the same measurement time.

Examples of pre-defined requirements or rules associated with differentoperations to reduce or limit degradation include:

a. In one example it may be pre-defined that if the center subcarrierwithin UE RF receiver BW is punctured then the UE has to meet the samerequirements for an operation as defined for the same operation when thecenter subcarrier is not punctured. This rule will require the UE toadapt its receiver to either apply compensation to the result of theoperation or avoid using signals received in the center subcarrier ofits RF receiver BW. This will require the UE to have additional radiocircuitry and processing resources, e.g. more memory and processingresources.

b. In another example it may be pre-defined that if the centersubcarrier within the UE RF receiver BW is punctured and the puncturedsubcarrier is not needed or used for an operation then the UE has tomeet the same requirements for the operation as defined for the sameoperation when the center subcarrier is not punctured.

c. In yet another example it may be pre-defined that if the centersubcarrier within UE RF receiver BW is punctured and the degradation inthe performance of operation is above a threshold, then the UE will notperform that operation and/or will not use or signal the results of thatoperation to the network node. For example, if the accuracy of the RSRPbecomes more than 2 dB worse than the normal accuracy (i.e. the accuracyachieved when center subcarrier is not punctured) than the UE may notsignal the RSRP results to the network node and/or not use it for anaction e.g. for cell reselection, positioning etc.

d. In yet another example it may be pre-defined that if the centersubcarrier within UE RF receiver BW is punctured then the UE still hasto meet the requirements for an operation but with some limiteddegradation with respect to those defined for the same operation whenthe center subcarrier is not punctured. This rule will also require theUE to adapt its receiver to either apply partial compensation to theresult of the operation or avoid using signal received in the centersubcarrier of its RF receiver BW. This rule may not require the UE toimplement or use as much extra circuitry and processing resources as inpre-defined requirement (a) above. This is further elaborated with fewexamples below:

For example, the UE may be allowed to meet an accuracy of +/−3 dBinstead of +/−2 dB for RSRP in case the center subcarrier of the RFreceiver BW is punctured.

In another example the UE may be allowed to measure RSRP and/or RSRQ ofup to 6 cells over the same L1 measurement period instead of 8 cells, incase the center subcarrier of the RF receiver BW is punctured.

5. Method in a Network Node of Allowing UE to Puncture Center Subcarrier

In this embodiment the network node may configure the UE to enable theUE to puncture the center subcarrier within the UE's RF receiver BW.This configuration mechanism will ensure that either network node or UEpunctures the center subcarrier but not both. The signalingconfiguration mechanism may be specified in different manners. This isexplained with several examples below.

In one example the UE may only puncture the center subcarrier if it isexplicitly permitted by the network node to puncture the centersubcarrier.

In another example the UE may puncture the center subcarrier by defaultbut such default behavior can be overridden or reversed by an explicitindication received from the network node. For example, if network nodeindicates that the UE is not allowed to puncture the center subcarrierthen the UE will not puncture the center subcarrier regardless of thedefault rule or UE behavior.

In yet another example the network node may send an indicator informingthe UE that the network node is or will puncture the center subcarrier.Upon receiving such indication, the UE will not puncture the centersubcarrier or stop puncturing the center subcarrier if the UE as doingso.

In yet another example the network node allows the UE to puncture thecenter subcarrier provided only certain types of signals are transmittedon the center carrier by the network node, e.g. a data channel such asPDSCH. The network node may also forbid the UE from puncturing certaintype of control/data signals sent on the center subcarrier, e.g. signalssuch as CRS which cannot easily be reconfigured at a different locationin frequency within the cell transmission BW.

The network node may also decide whether or not to permit the UE topuncture the center subcarrier within the UE's RF receiver BW based onone or more criteria. Examples of such criteria include:

a. The number of UEs configured with the same center subcarrier in thesame cell. In this case in one example if the puncturing of the centersubcarrier of all the UEs is feasible then the network node may decideto puncture the center subcarrier of the UEs itself. But in case thenetwork node only wants to allow a subset number of UEs to puncturetheir center subcarriers, then the network node configures the UE withexplicit indication, i.e. whether a certain UE is allowed or not topuncture the center subcarrier.

b. Processing capability in network node. The network node would requireextra resources to puncture the center subcarrier. If there is a largenumber of UEs with different center subcarriers in the cell, thenpuncturing of the center subcarrier may consume more resources in thenetwork node. In this case the network node may only selectivelypuncture the center subcarrier itself and may configure the remainingUEs to puncture their respective center subcarriers.

c. UE capability of puncturing center subcarrier. All UEs may not becapable of puncturing their own center subcarrier. For such UEs thenetwork node may itself puncture the center subcarrier. The network nodemay only configure UEs which are capable of puncturing their centersubcarrier, to puncture their respective center subcarrier. The networknode may determine the UE capability based on an explicit indication(e.g. UE capability information) received from the UE. The UE capabilityinformation may further indicate that the UE is capable of performingone or more radio operations (e g channel estimation, measurement etc)and meet the corresponding pre-defined requirements even if one or moreradio signals used for such operations are received over the centersubcarrier of the UE's RF receiver BW.

FIG. 11 is a block diagram of a device 100 that is configured to performoperations according to one or more embodiments disclosed herein. Thedevice 100 includes a transceiver(s) 710, a processor circuit(s) 700(referred to as processor for brevity), and a memory device(s) 720(referred to as memory for brevity) containing functional modules 722.The device 100 may further include a display 730, a user input interface740, and a speaker 750.

The transceiver 710 is configured to communicate with a network nodethrough a wireless air interface using one or more of the radio accesstechnologies disclosed herein. The processor 700 may include one or moredata processing circuits, such as a general purpose and/or specialpurpose processor, e.g., microprocessor and/or digital signal processor.The processor 700 is configured to execute computer program instructionsfrom the functional modules 722 of the memory 720 to perform at leastsome of the operations described herein as being performed by a UE.

FIG. 12A is a block diagram of a network node 800 that is configuredaccording to one or more embodiments disclosed herein for a radionetwork node, an access node, or other network node. The network node800 can include a transceiver 810, a network interface(s) 840, aprocessor circuit(s) 820 (referred to as processor for brevity), and amemory device(s) 830 (referred to as memory for brevity) containingfunctional modules 832.

The transceiver 810 is configured to communicate with the UE 100 usingone or more of the radio access technologies disclosed herein, when thenetwork node 800 is a radio network node. The processor 820 may includeone or more data processing circuits, such as a general purpose and/orspecial purpose processor, e.g., microprocessor and/or digital signalprocessor, that may be collocated or distributed across one or morenetworks. The processor 820 is configured to execute computer programinstructions from the functional modules 832 of the memory device(s) 830to perform at least some of the operations and methods of describedherein as being performed by a network node. The network interface 840communicates with other network nodes and/or a core network.

FIG. 12B is a block diagram that illustrates the functional modules 832of the memory 830 in more detail. As shown therein, the functionalmodules 832 may include a signal puncturing module 834, a nodeconfiguration manager 836 and a UE configuration manager 838. Althoughillustrated in FIG. 8B as residing within the same network node, it willbe appreciated that the signal puncturing module 834, node configurationmanager 836 and UE configuration manager 838 can be implemented inseparate network nodes. The signal puncturing module 834 punctures asignal to null or remove a subcarrier corresponding to the centerfrequency of an RF BW of a UE prior to transmission. The nodeconfiguration manager 836 controls the configuration of the network node800 and may configure or adapt the network node 800 as described aboveto adapt the transmission of one or more control/data radio signalswithin the UE RF reception BW in a manner that reduces or avoids thetransmission of the radio signals over the subcarrier that correspondsto the center frequency within the UE RF reception BW. The UEconfiguration manager 838 may provide instructions to a UE to adapt itsconfiguration to reduce or minimize performance degradation of one ormore radio operations that utilize or rely on one or more radio signalsreceived over the center frequency at the UE RF receiver BW.

ABBREVIATIONS

Explain all abbreviations and acronyms used in the document.

Abbreviation Explanation

ADC Analog-to-digital converter

BS Base Station

CID Cell Identity

CRS Cell-specific Reference Signal

DL Downlink

FOM Figure of Merit

ID Identity

L1 Layer 1

L2 Layer 2

LTE Long Term Evolution

M2M Machine to Machine

MAC Medium Access Control

MDT Minimization of drive test

MTC Machine Type Communication

OFDM Orthogonal Frequency Division Multiplexing

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

PHICH Physical Hybrid ARQ Indicator Channel

PSS Primary Synchronization Signal

RAT Radio Access Technology

RE Resource Element

RB Resource Block

RRM Radio Resource Management

RSRQ Reference signal received quality

RSRP Reference signal received power

SSS Secondary Synchronization Signal

UE User Equipment

As will be appreciated by one of skill in the art, the present inventiveconcepts may be embodied as a method, data processing system, and/orcomputer program product. Furthermore, the present inventive conceptsmay take the form of a computer program product on a tangible computerusable storage medium having computer program code embodied in themedium that can be executed by a computer. Any suitable tangiblecomputer readable medium may be utilized including hard disks, CD ROMs,optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchartillustrations and/or block diagrams of methods, systems and computerprogram products. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable memory that can direct a computer or other programmable dataprocessing apparatus to function in a particular manner, such that theinstructions stored in the computer readable memory produce an articleof manufacture including instruction means which implement thefunction/act specified in the flowchart and/or block diagram block orblocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide steps for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

The functions/acts noted in the blocks may occur out of the order notedin the operational illustrations. For example, two blocks shown insuccession may in fact be executed substantially concurrently or theblocks may sometimes be executed in the reverse order, depending uponthe functionality/acts involved. Although some of the diagrams includearrows on communication paths to show a primary direction ofcommunication, it is to be understood that communication may occur inthe opposite direction to the depicted arrows.

What is claimed is:
 1. A method in a user equipment (UE) served by acell managed or served by a network node, the method comprising:determining that a center frequency of a radio frequency (RF) receptionbandwidth of the UE is different than a center frequency of a RFtransmission bandwidth of the cell serving the UE; receiving a signalfrom the cell serving the UE over a center subcarrier within the RFreception bandwidth of the UE; and puncturing a portion of the signalreceived over the center subcarrier within the RF reception bandwidth ofthe UE.
 2. The method of claim 1, further comprising adapting one ormore procedures to reduce a performance degradation of one or more radiooperations that utilize or rely on one or more radio signals receivedover the center frequency of the RF reception bandwidth of the UE. 3.The method of claim 2, wherein adapting the one or more procedures toreduce the performance degradation is based on pre-defined rulesassociated with the one or more radio operations.
 4. The method of claim3, wherein adapting the one or more procedures based on the pre-definedrules comprises: applying a value of compensation to a result of the oneor more radio operations; and/or using a signal that does not correspondto the signal received from the cell over the center subcarrier.
 5. Themethod of claim 1, further comprising: identifying a control signalbased on a frequency of use of the control signal, a frequency oftransmission of the control signal, and/or a significance of the controlsignal; and transmitting an indication of the identified control signalto the network node.
 6. The method of claim 5, further comprisingreceiving information from the network node that the identified controlsignal has been moved from the center subcarrier that corresponds to thecenter frequency of the RF reception bandwidth of the UE to a subcarrierthat does not correspond to the center frequency of the RF receptionbandwidth of the UE.
 7. The method of claim 5, wherein the signalreceived from the cell is different from the identified control signal.8. The method of claim 1, wherein puncturing the portion of the signalreceived over the center subcarrier comprises performing a fast Fouriertransform of the signal to generate a plurality of frequency bins andzeroing a frequency bin corresponding to the center subcarrier.
 9. Auser equipment (UE) served by a cell managed or served by a networknode, the UE comprising: processing circuitry; a transceiver coupled tothe processing circuitry; and memory containing instructions executableby the processing circuitry whereby the UE is operative to: determinethat a center frequency of a radio frequency (RF) reception bandwidth ofthe UE is different than a center frequency of a RF transmissionbandwidth of the cell serving the UE; receive a signal from the cellserving the UE over a center subcarrier within the RF receptionbandwidth of the UE; and puncture a portion of the signal received overthe center subcarrier within the RF reception bandwidth of the UE. 10.The UE of claim 9, wherein the UE is further operative to adapt one ormore procedures to reduce a performance degradation of one or more radiooperations that utilize or rely on one or more radio signals receivedover the center frequency of the RF reception bandwidth of the UE. 11.The UE of claim 10, wherein the UE is further operative to adapt the oneor more procedures to reduce the performance degradation based onpre-defined rules associated with the one or more radio operations. 12.The UE of claim 11, wherein the UE is further operative to adapt the oneor more procedures based on the pre-defined rules by: applying a valueof compensation to a result of the one or more radio operations; and/orusing a signal that does not correspond to the signal received from thecell over the center subcarrier.
 13. The UE of claim 9, wherein the UEis further operative to: identify a control signal based on a frequencyof use of the control signal, a frequency of transmission of the controlsignal, and/or a significance of the control signal; and transmit anindication of the identified control signal to the network node.
 14. TheUE of claim 13, wherein the UE is further operative to receiveinformation from the network node that the identified control signal hasbeen moved from the center subcarrier that corresponds to the centerfrequency of the RF reception bandwidth of the UE to a subcarrier thatdoes not correspond to the center frequency of the RF receptionbandwidth of the UE.
 15. The UE of claim 13, wherein the signal receivedfrom the cell is different from the identified control signal.
 16. TheUE of claim 9, wherein the UE is operative to puncture the portion ofthe signal received over the center subcarrier by performing a fastFourier transform of the signal to generate a plurality of frequencybins and zeroing a frequency bin corresponding to the center subcarrier.17. A non-transitory computer-readable storage medium comprisinginstructions for configuring a user equipment (UE), the UE being servedby a cell managed or served by a network node, wherein the instructionswhich, when run by a processor of the UE, cause the UE to: determinethat a center frequency of a radio frequency (RF) reception bandwidth ofthe UE is different than a center frequency of a RF transmissionbandwidth of the cell serving the UE; receive a signal from the cellserving the UE over a center subcarrier that corresponds to the centerfrequency of the RF reception bandwidth of the UE; and puncture aportion of the signal received over the center subcarrier within the RFreception bandwidth of the UE.
 18. The non-transitory computer-readablestorage medium of claim 17, wherein the instructions further cause theUE to adapt one or more procedures to reduce a performance degradationof one or more radio operations that utilize or rely on one or moreradio signals received over the center frequency of the RF receptionbandwidth of the UE.
 19. The non-transitory computer-readable storagemedium of claim 17, wherein the instructions further cause the UE topuncture the portion of the signal received over the center subcarrierby performing a fast Fourier transform of the signal to generate aplurality of frequency bins and zeroing a frequency bin corresponding tothe center subcarrier.
 20. The non-transitory computer-readable storagemedium of claim 17, wherein the instructions further cause the UE toreceive information from the network node that a control signal has beenmoved from the center subcarrier that corresponds to the centerfrequency of the RF reception bandwidth of the UE to a subcarrier thatdoes not correspond to the center frequency of the RF receptionbandwidth of the UE to the UE within the UE RF reception bandwidth.